Injectible two-staged rotary compressor and heat pump system

Abstract

In an injectable two-staged rotary compressor, a second suction pipe includes a heat-exchange promoting unit that promotes heat exchange between intermediary-pressure injected refrigerant and internal space or an external surface of a sealed container. The heat being exchanged by the intermediary-pressure injected refrigerant absorbing heat.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an injectable two-staged rotary compressor and a heat pump system.[0003]2. Description of the Related Art[0004]The gas injection cycle is advantageous in that it increases the amount of refrigerant circulated through a heat radiator, and improves a heat-radiating capacity (heater capacity or water heater capacity). These advantages are achieved by having a structure in which a compressor sucks in additional refrigerant also during a compression process. Especially in cold regions, the amount of the circulated refrigerant decreases, because a base gas sucked into the compressor is diluted because of cold; therefore, it is effective to increase the amount of circuited refrigerant by an injection. Even if the injection is performed during the compression process, the amount of the refrigerant circulating through an evaporator stays the same, because the amount of the circulated refrigerant ...

AI Technical Summary

Benefits of technology

[0004]The gas injection cycle is advantageous in that it increases the amount of refrigerant circulated through a heat radiator, and improves a heat-radiating capacity (heater capacity or water heater capacity). These advantages are achieved by having a structure in which a compressor sucks in additional refrigerant also during a compression process. Especially in cold regions, the amount of the circulated refrigerant decreases, because a base gas sucked into the compressor is diluted because of cold; therefore, it is effective to increase the amount of circuited refrigerant by an injection. Even if the injection is performed during the compression process, the amount of the refrigerant circulating through an evaporator stays the same, because the amount of the circulated refrigerant is determined by a basic displacement capacity and a rotation frequency of the compressor. However, it is possible to improve evaporating capacity (cooler capacity) too, by liquefying the refrigerant in a gas-liquid separator, or providing additional overcooling in an internal heat exchanger at an entry point to the evaporator.

[0004]The gas injection cycle is advantageous in that it increases the amount of refrigerant circulated through a heat radiator, and improves a heat-radiating capacity (heater capacity or water heater capacity). These advantages are achieved by having a structure in which a compressor sucks in additional refrigerant also during a compression process. Especially in cold regions, the amount of the circulated refrigerant decreases, because a base gas sucked into the compressor is diluted because of cold; therefore, it is effective to increase the amount of circuited refrigerant by an injection. Even if the injection is performed during the compression process, the amount of the refrigerant circulating through an evaporator stays the same, because the amount of the circulated refrigerant is determined by a basic displacement capacity and a rotation frequency of the compressor. However, it is possible to improve evaporating capacity (cooler capacity) too, by liquefying the refrigerant in a gas-liquid separator, or providing additional overcooling in an internal heat exchanger at an entry point to the evaporator.

Problems solved by technology

In addition, to maintain the reliability of a compressor, the compressor must be limited in operating pressure ratio and rotation frequency.

However, in the conventional gas injection cycle, the reliability decreases if too much liquefied refrigerant is mixed into the injected refrigerant.

Because, too much of liquefied refrigerant reduces the viscosity of the lubricants, causing defective lubrication or defective sealing, and increase in bearing loads with still more liquefied refrigerant being mixed (for an example, see Japanese Patent Application Laid-Open No. 11-132575).

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